Arrangement for the reception of electric oscillations



Nov. 24, 1931. F. FISCHER 1,833,323

ARRANGEMENT FOR THE RECEPTION OF ELECTRTC OSCILLATIQNS Fi led Dec. 23,1925 Qenera'tor Audible fragmen E I 2 .6 l9 /0 g E Q I I I j ZZ /1' -2/@j j/flbl" of ,4 1' e re v n q f g INVENTOR HUTZ FISCHER TTORNEYPatented Nov. 24, 1931 i rnf r zr 'rscnnn, or BERLIN; GER A stems rocnsnnnsoirnnr nun n-nnnrnosn ER ANY RAPHIE 'M; B. H. HnLLEsoHEs,onBnnnm; GERMANY, A coercerron on 1 nnmmen unnrro'nrimnncnrrrcnornnnermooserrinnrrons U Application fileglbecember 23,-.1'925; serial No."77,201, and inj'GermanyUFebruary 17, 1925.

Battery 23 L furnishesgtub e R1" 1 :The present invention relates to aineans for providing an exceptionally sensitive arrangenent adaptedforthefreceptron of electrical oscillations. i fMore specifically, 1nyinvention relates'to an improved means adapted for telegraphic receptionon shortwaves. u 7

The novel features which I believeto be characteristic of my inventionare set-forth with, particularity in the] appended claims;

The inventio n itself, however; asito its organization and method ofoperation together i with further objects and advantages thereofwillbest be understood by reference :to the following description takenin connection with the accompanying drawings, in which;

Figure .1 represents arrangement showtion; and, I

'Figure 2 shows a modification wherein the receiving circu t is adaptedto be loosely coupled to the transmitting circuit. p

In Figure 1 an antenna circuit Ahaving inductances 1, 2 and a variablecondenser 3 is ing one preferred embodiment of my invenshown. B is areceiving circuit made up of thermionic valve R of the usual three-olement type having an output clrcultincluding telephone receiver T, platecurrent source 15 and an input circuit which comprises the tuned circuitmade up of inductance 4 and variable condenser 14 and grid condenser 12and a grid resistance 13 all connected in Well known manner. Thefilament currentsupply for tube R is shown by battery 16. Circuit 13 isloosely coupled to inductance '1 of an tenna A through coil 4. Alsocoupled to the antenna A through inductance 2 thereof by means of coils5 and 6 is a second thermionic valve circuit C composed of a thermionicvalve R filament current source 17, input circuit coil 6, output circuitcoil 5 and a plate source 9, a generator of audible frequency.

i th filament currentas rin"Figure,l and source is adapted to serveathesa ne func-o Q tion as gsiinilarldevice in Figure 1. In the T output oftuloeglit ,in' series'with, the plate thereof,there'isconnectedacouplingwinding- 1 l0 ser v ing toicou-ple circuit Cfwith the input circuit11,'- 18f of tube R5,] resistance 20 and condenser 19:, corresponding.to andhaving the-identical function of devices liijtand 12 I 6 ofFigure The' translator as hefore is represented by the plate "supply by22 and tlleusual filament sourcefrbyi 21 As willibe [noted Figure-2differentiates froinFigureul by that-the receiven circuit B is looselycoulpled through 10 ll to the-transmitting circuit Cfinstead of pantenna A as 'infEigureil.l

. Enema when; hath instances is as ly coupledto' the antenna with aresult that;

:there; is produced marked reduction in 'dampinginv the antenna circuitdue the i retroactivecouplingof thecircuit C. f v

The ,d vice operates-as f llows; Circuit C is -so adjusted that itis'almost atjthe' oscilla tion point, thus, when lin'corning energy jstrikes the [antenna "the" transfer of energy .I

. froln the antenna to circuit C causes circuit C tospill over With aresult that hig l equency-oscillations will be generated. fHo'wever duetohthe platesupply et circuitiC being an alternating current sourceitisfevident that for half 7 of each cycle the plate of tube R .,\vill benegative with a result that i for that halfcycle oscillations cease. The

result; is, that-the high frequency' oscillations I generated by tubeRare periodically-stopped oriwhat mighthe called chopped up at an audiblefrequency] This, of course, is equivalent to -modulati ig h hig r qu cybyaudible frequencyfenergy; These modulated hi glr' frequencyoscillations: are irnpressed on v the'circuit through the loose coupling1,4 of Figure 1 or 10,'1'1':in Figure 2, detected and fe'd 'to thetranslator device"T wherethe Sig nals lnay be'heard, *It is evident'from the foregoing that when high frequency signal energy ceases theoscillations in circuit C Will also'cease even though the'pl a te"returns pe riodical lytea-positive state,

V A- number of other forms of construction of the device areconceivable; *for instance, modulation of the locally generated highfrequency oscillations can be ei'lected byvarying the grid potential ofthe electron tube R; I

with the rhythm of an audible frequency.

7 This feature could be accomplished by simply vplacing a source ofaudible frequencyrcur- {rent-in the-grid circuit of tube R either di"rec tly or indirectly. As stated before the re ceiver need not bedirectly coupled to the antenna but as shownin Figure Zrnay be looselycoupled with a'local wave generator.

Another advantageous. feature of the ar rangement set forth conformablywith the invention consists in'the fact-that the'iecei'ver appreciablyexcited only at times When 1 1' oscillations ares'et' up ,infthe loca-lgenerator so that duringthehalf'cycles of audible fre-V -quency 'usedforfeeding the electron tube R When the anode potential isnegative no gen-7 ferationofoscillations takes'place, thus, at

" the sam': time"audioirtube'Rg remains unexcitedif This featurelof'theinventioninsures, greater freedom from disturbances of I the receivingarrangement 'especially from at- I 'inosphericswhich the antennaisexcited by "shock. In this scheme it is feasible to have re course to"verylo'ose couplingof the receiver uo'a'nd antenna whichfhoweveryisadequately strongforreceptionpurposessince the receivmg energy isgenerated locally; Another ad vantage resides in the 'fact that thereception of signals is independent of variations ofthe incoming 1 highfrequency currents; This reference to specific forms and arrangementsshown for the accomplishment .of' my pur pose it will be understood thatother embodimefnts' may be used without departing from the spirit of my"invention or the scope of the appended claims.

of my. invention what I claim as newand usefill and to secure'by LettersPatent Ieo g 1. Inian arrangement for the r'cepaea f '55{electricoscillations, in combination, an an itenna and aregeneratively:coupled electron tube circuit in close'coupldrelationwith said antenna,ai1d so arrangedand, adjusted that the. said circuitset into oscillationlunder the actionof incom ng signals, meansto-control the .high frequency oscillations by 7 lowfrequency;oscillations of audible frequency and receiving circuitininductive relationship to; said regenerativelywoupled electronHaving'nowset' forththeob-] 'ect and nature 7 uponsaid circuit forpreventing 'the genera-,1 'tion of oscillations at theendof a signal .2.In an; arrangementi for; the reception of electric oscillations, anantenna circuit, a regeneratively coupled electron tube" clrcu t na,means controlled-by incoming signals to frequency signals audible andfor'rendering said regenerativelyf coupled, circuit inoperative at theend of a signalimpulse, and are- 7 ceivmgcircuit ansmductive relation tosaid p .1 v o u. r tor recelving and translatmg sa d controlled signals.5

regeneratively coupled electron tube circuit 7 In a device ofthexkihddescribed re ceiving circult coupled to. an electron tube c1rcu1t,'-anantenna circuit and a regenerative;

quen'cy oscillations, means comprisin'gan al 1 ternating'current-sourceof audible" frequency in close cou-pledrelationship with'said antena seta n;t eic ifi,i t e eilla ie ineanscoinprlsing a source of low frequency.osc'illations'for rendering saidincoming high 'i i ly coupledfelectrontube'circuit in close'coupled relationship therewith, said last namedcircuit being so arranged that'it is set into oscillation when struck byincominglhig h frein the plate circuit of said electron tube cir in said"circuit and received'in said receiving 1 circuit, said alternatingcurrent means also ac'tingupon said oscillation circuit for prevent ngthe generation of oscillations at the end of a signal.

tube circuit, saidlast named-means also acting V DR. FRITZ FISCHER?" r qI j I ean; whereby a modified wave may be setup

